Preheat the oven to 350°F.
In a large bowl, combine the onion soup mix, pineapple juice, broth, tahina, garlic, salt and pepper to taste, lemon juice, and ¼ cup water.
Trim the brisket of most of the fat. Place in a shallow baking pan and rub with the onion-tahina mixture, making sure there is at least 2 inches of liquid beneath the meat. If there’s not enough, add more water. Scatter the sliced onion on top.
Bake, covered with heavy-duty aluminum foil, for 2 to 3 hours, or until the meat is fork-tender. If it is too dry after an hour, add more broth or pineapple juice.
When done, remove the meat from the sauce and cool. Refrigerate the sauce so that the fat can be removed. Slice the meat against the grain and place it in a pan. Cover with the sauce. If it is too thick, again blend in some pineapple juice or water to thin it out. When ready to serve, preheat the oven to 350°F. Cover and heat in the oven until hot, about 45 minutes, and serve.
—From The Brisket Book by Stephanie Pierson/Andrews McMeel Publishing